A number of automatic bending machines containing a bending head with a bending pin, a bending arm, and a bending support are well-known, for example, from the patent documents U.S. Pat. Nos. 6,009,737 and 5,495,740. The bending arm is, along with the bending pin, coupled to a bending drive for joint rotation of the bending arm and the bending pin about the longitudinal axis of the bending pin. The bending arm contains a bending plate, which is reversibly displaceable towards and away from the bending pin and is coupled to the drive. The bending head further contains a bending support, which is provided with a support plate, which is reversibly displaceable with its drive to a position in front of the bending pin and the bending arm in which the bent material is situated during a bending operation. The drives of the individual components of the automatic bending machine, i.e. the drives of the bending arm and bending support, the drives of the positioning and gripping device of the bent material, as well as the bending drive, are coupled to a control mechanism of the automatic bending machine, which coordinates their operations, thus controlling the overall operation of the automatic bending machine.
CZ PV 2006-289 discloses a bending head for an automatic bending machine containing a longitudinal bed with a positioning and gripping device, whereby the bending head contains a bending support with an adjustable support plate that is provided with a shape groove for the bent material and is coupled to a drive coupleable to the control mechanism of the automatic bending machine. The support plate is mounted on a support pin, which is slidingly mounted in the body of the bending support, whereby it is coupled to an outlet member of a linear drive that is coupled to the control mechanism of the automatic bending machine. The bending support is provided with a locking device of the bending plate.
CZ UV 24556 describes a bending device containing a longitudinal bed with a movable positioning and gripping device, which is aligned with a bending head containing a jointly rotatable bending pin and bending arm with an adjustable bending plate. The longitudinal bed is made up of longitudinal segments, whereby at one end of the longitudinal bed is selectably mounted a linear magnetic motor coupled to a positioning and gripping device or an electric servo motor with a motion belt coupled to the positioning and gripping device. At the other end of the longitudinal bed is located a vertically and laterally adjustable bending head, whose bending arm is selectably situated on the right or left side of the bending head. The bending plate on the bending arm is selectably composed of a bending stone or a bending roll, or a bending roll with defined rolling away along the bent material during the bending operation.
A common disadvantage of the bending heads known so far from the background art is the fact that, without substantial rearrangement, they only allow to perform bends in one direction, i.e. by turning the bending roll either only to the right, or only to the left. If need arises to change the direction of bending, it is necessary either to use two separate bending heads with opposing rotation direction of the bending roll, which is demanding in economic terms and decreases the effective utilization of the two bending heads, or it is necessary to rearrange the bending head to enable the opposite direction of rotation of the bending roll, which is economically challenging, since during the rearrangement the bending machine is blocked and is out of operation, or it is necessary to turn the bent material, which places increased demands on handling devices and the space around the bending machine, as a number of bent products have a relatively large length. Another disadvantage of the background art is the fact that the feasibility of conducting two or more bends in immediate succession is limited, or it can only be done with a minimal length of a straight section between the bends.
The aim of the invention is to enable selectable and fast utilization of bends in both directions on a single device without having to rearrange the device, while still maintaining productivity, accuracy, sufficient simplicity of the device and its long service life, and at the same time to allow individual bends to be arranged immediately one after another or only with a minimal spacing, i.e. minimal straight sections between each other.